Vacuum system



O Umted States Patent u 13,545,500

[72] lnventors ligbeell'lt J-BOVO [56] References Cited Arnold E.Westlund,Jr., Gloucester, "9 l I] 5 2 ENTS Massachusetts reat rltam55/309 [2l 1 Appl. No. 692,499 Primary Examiner-Houston S. Bell, Jr..[22] Filed Dec. 21, 1967 Attorneys-Norman J. OMalley and Laurence Burns[45] Patented Dec. 8, 1970 [73] Assignee Sylvlnla Electric Products Inc.

r corporation Delaware ABSTRACT: A vacuum system comprising a two-phasepumping arrangement that is connected over a main conduit to a remotelydis osed evacuation s stem. The main conduit is [54] VACUUM SYSTEMnormally closed-Exfi during the first phase of evacuation by a 4 cmmslDrawing plunger associated with an electrical solenoid. A screened [52][1.8. CI. 141/65, detour conduit is provided around the blocked mainconduit.

, 55/312, 55/428, 55/511 Thereby, the first pump phase evacuates airfrom the article [5| 1 Int. Cl. B65b 31/04 over the screened detourpath, filtering out unwanted particles [50] Field of Search 141/93, 65,that are collected in a trap well positioned adjacent the screen 66.8.286(lnquired); 55/270, 309, 312, 313, 314, 428, 429, 432, 433, 503,5i1(lnquired);62/(lnquired); 230/(lnquired); l37/(lnquired) area. Thesecond and final phase of evacuation is initiated after the solenoid isenergized to remove the block from the main conduit.

VACUUM SYSTEM BACKGROUND OF THE INVENTION 1. Field of the Invention i nthe initial surging cycle, the evacuation of air and/or other gases fromthe article 14 collects residue or particle's left This invention isdirected to hydraulic vacuum systems but 5 more specifically to vacuumpumps where an article fitted to the pumping system can be evacuatedfrom an atmospheric condition to a given vacuum. Normally, a device ofthis type employs a series of pumps that provide a rough and finepumping combination to achieve a desired vacuum of an article.

2. Description of the Prior Art Articles of work that require evacuationsuch as bell jars, lamp envelopes, etc. are normally attached directlyto a central orifice of a pumping system. A series of interconnectedmechanical and diffusion pumps are then operated to evacuate gas fromthe article to a desired vacuum. Usually a first pumping-down called a purge or rough-pump is accomplished by a mechanical pump. This initialsurge of evacuated currents frequently sweeps .or cleans out anysediment or residue lefl in the article from a previous step offabrication. The sediment is drawn fromthe article to an evacuation portby way of the internal mechanism of the pump. The particles collectwithin the pump mechanism which necessitates frequent repairs, Also,constant ingestion of these particles can necessitate, earlyreplacementof the pump. Even with expensive practices such as aircleaning of the article prior to evacuation failed to reduce the costlydowntime and early replacement of the pump.

SUMMARY or THE lNVENTlON In our invention we have overcome theseproblems by designing a built-in sediment trap fully operativeduring thefirst purge cycle of the evacuation of the article. 7 During the firstcycle, a new'route from the article to pump is established by blockingthe main route. This new route is provided with a screened trap thatprevents residue and sediment from reaching the pump. This purge cycleisof short duration. and at its termination automatically actuates afine pumping or diffusion pump cycle.

Just prior to initiation of the fine pumping cycle, the block is removedfrom the main route. This allows a direct, unscreened path from thearticle to the pump providing high speed evacuation of the article.

This unique system provides a trouble-free cleansing ar' rangement of anarticle for an unlimited usage in vacuum systems.

These and other objects, features and advantages of the invention willbe apparent from the following specification when taken in conjunctionwith the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING The drawing is a schematic view of anevacuation system showing in particular the article and pumping sourceand the interconnected piping therebetween.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing,ourembodiment of a sediment trap comprises a piping system of standardtubular configuration. The pumping system generates from a main pumpingsource 10 to an article manifold 12. in a specific example we describeand illustrate a leak detector apparatus showing 'how a sediment of ourdesign would function.

In a leak detector operation, series of pumps are utilized for attaininga desired vacuum withinan article. The two pumps most commonly usedare astandard mechanical pump and a diffusion pump. In the first phase ofpumping the mechanical pump is initiated to introduce a pumping cyclewhere the infrom a previous operation and carries this sediment back tothe pumping source '10.

To prevent this sediment from reaching the intricate pumping mechanismwe detour the main straight route from article topump. Thecompletetubular piping system can be clearly seen in the illustration ofthe drawing where a straight main pipe 16 having one end affiired to thepumping source 10 and the other end fitted with a short upturned run 18.An article manifold adjustable fitting 12 is positioned thereto, with aconventional knurled closure ring 20 capable of being rotated to receiveand hold an article.

The main pipe l6 is provided with two spaced apart shortrun legs 22 and24 extending down fro-m the pipe 16. The legs 22 and 24 mate withcoinciding short legs 28 and 30 of a sediment trap 26. The legs 28 and30 are extensions of a straight The legs 22 and 24 are joined to thelegs 28 and 30 by standard compression rings 34 and-36. The joining oflegs 22 and 24 to legs28 and 30 must be attained'with complete air tightjoints and is accomplished by using compressible gaskets between thejoi'ned ends. ln'the fitting of leg 24 to leg 30, a simple 0-ring gasket38 is placed between the ends and then compression ring 36 is affixed tocompletely seal this joint.

The joining of legs 22 and 28 are done in asimilar manner with theexception that a screen 40 is spaced between two 0- ring gaskets 42 andthen'the compression ring 34 is secured thereto.

A lower extending leg 44 in register with leg 28 defines a sediment well46 which is provided with a removable screw To complete the device,asolenoid 50 having a coil 51 is fitted to the top area of the main pipe'16. The solenoid is provided with "an internal blocking plate 52 fittedwithin guideways 54 of the pipe 16 and guide between the coil 51 of thesolenoid 50. Normally, the blocking plate 52 is spring urged in theopening of pipe 16 by a spring 56.

be described. An article 14 is fitted into the manifold 12 by rotationof the knurled closing ring 20. Articles of different configuration canbe accepted by interchangeable manifold fittings. As mentionedpreviously, the pumping source is initiated with a purge flushaccomplished by a mechanical pump. It may be noted at'this time that themain pipe 16 is closed by block 52. Therefore air evacuated from thevessel or article 1.4 is drawn over the detour path, designated in thedrawing by the broken arrows. This first rush of air carrying anyparticles of residue follows the bypass piping 24, 30, 32 and 28 wherethe particles are trapped by the screen 40, positioned between legs 22and 28. The filtered air continues through the screen and completes itscircuit back to the pumping source 10.

At this particular time the operation, the mechanical pump is isolatedfrom the system and a diffusion pump, a part of the pumping source 10,is put into operation. Just prior to the operationof the diffusion pumpthe solenoid 50 is activated thereby removing the block by means ofenergizing the coil 51. As mentioned previously, the diffusion pumpaccom plishes the desired vacuum of the article in this case a vacuum inthe vicinity of 10- microns. With the block 52 removed from the mainpipe 16 a direct run from article to pump is established where residueclear air is rapidly drawn back to the pumping source 10. After thearticle has been evacuated to the desired vacuum, the analysis of thepart being evacuated is made, then the part and system is put back toatmosphere. A new article can be fitted to the manifold and theoperation is repeated.

During isolation shutdown .of the pumps, and during attachment of a newarticle to the manifold any sediment caught A complete sequence of anevacuation of an article will now' An added precaution to catch andretain minute sediment particles in the traparea is accomplished bycoating the inner walls of the trap area with a low vapor pressure gritcatching grease. When this grease is used the complete trap piping hasto be taken 011' and cleaned, this isaccomplished by removing thecompression rings 34 and 36. The trap operates normally without thegrease, but if added protection is required, this can be utilized.

It is apparent that modifications and changes can be made within thespirit and scope of the instant invention, but it is our arranged sothat said blocking means can be bypassed; filter means fitted withinsaid detour path;

gases from the article to be evacuated being directed through saiddetour path and hence said filter when the mechanical pump is actuatedand thence being directed through said main evacuation line when saiddiffusion pump is actuated, whereby extraneous particles are filteredfrom the gases andprevented from entering the pumping source when saidmechanical pump is actuated.

2. The vacuum pumping system according to claim 1 wherein a sedimenttrap is disposed below said filter means and includes a removable cappedwell, whereby particles caught in the screen are collected therein.

3. The vacuum system according to claim 1 wherein said blocking meanscomprises an electrical solenoid having a plunger defined as a block,said plunger normally spring urged to block said main evacuation lineand when energization of said solenoid thereby removes said plunger fromsaid main evacuation line after said rough pumping cycle is completed.

4. The vacuum system according to claim 1 wherein said filter means is ascreen.

